In December 2003, Brent Cambron gave himself his first injection of morphine. Save for the fact that he was sticking the needle into his own skin, the motion was familiar--almost rote. Over the course of the previous 17 months, as an anesthesia resident at Boston's Beth Israel Deaconess Medical Center, Cambron had given hundreds of injections. He would stick a syringe into a glass ampule of fentanyl or morphine or Dilaudid, pulling up the plunger to draw his dose. Then he'd inject the dose into his patient. If the patient had been in a panic before her surgery, Cambron would watch her drift into a pleasant, happy daze; if the patient had been moaning in pain after surgery, he'd watch the relief spread across her face as the pain went away. It was understandable, perhaps, that Cambron was curious to experience these sensations himself, to feel what his patients felt once the drugs began coursing through their bodies. It could even be considered a clinical experiment of sorts. "I had thought about it for a long time," he later confessed.

The way in which Cambron handled his own injection reflected that intense curiosity--but also a degree of caution. Although Cambron had been a physician for less than two of his 30 years, in that brief time he'd acquired a fund of knowledge that left him certain he knew what he was doing...